Windows Phone 8.1 will work as usual "at this time," and the current Windows 10 Mobile is still fully supported.

However, Microsoft has said that Windows 10 Mobile is no longer a focus, and users shouldn't expect new features or hardware.

It's no secret by now that Microsoft's smartphone ambitions are basically over, with its current Windows 10 Mobile operating system barely on life support.

So here's another nail in the coffin. On Monday, Microsoft announced in a blog post that any phone running the older Windows Phone 7.5 or 8 operating systems will no longer receive push notifications. Plus, the "Find my phone" function on those operating systems will no longer work, either.

This isn't necessarily going to affect a whole lot of users: Windows Phone 7.5 was first released in 2011, and Windows Phone 8 dropped in 2012. Despite the nomenclature, they were totally different operating systems: Windows Phone 7.5 hardware couldn't upgrade to Windows Phone 8. Neither operating system found a huge audience at the time, and there likely aren't many phones out there using it today — which is part of why Microsoft currently finds itself in this suboptimal smartphone situation in the first place.

If you're one of the few using the more recent Windows Phone 8.1, which dropped in 2014, Microsoft writes that everything will still work as usual "at this time." The phrasing here keeps the door open that things could change in the not-so-distant future.

Meanwhile, Windows 10 Mobile, which launched in 2015, is still fully supported by Microsoft. At least, technically: While all of its current features still work the same as they ever did, Microsoft announced in October that users can only expect security patches and minor improvements, not major new features or new hardware.

So, yes, here's another milestone in the march to the grave for Windows on smartphones.